This invention relates to a fuel injection rate deducing system for a diesel engine.
The rate of fuel injected into combustion chambers can be used as a reliable parameter for controlling, for example, exhaust gas recirculation in a diesel engine. A fuel injection pump driven by the engine supplies a controlled quantity of fuel to engine combustion chambers. Some fuel injection pumps have an accelerator lever to change the rate of fuel injection. In this case, the angular position of the accelerator lever and the rotational speed of the engine can be used to deduce the rate of fuel injection (see SAE 800167). However, such deduction is somewhat inaccurate, since the relationship between the angular position of the accelerator lever and the rate of fuel injection at a constant rotational speed of the engine varies with the temperature and the age of the fuel injection pump. On the other hand, it is generally difficult to directly measure the rate of fuel injection.